o.sca.lake 3.0: Total Scattering for Nanotechnology on the Como Lake is the 3rd edition of a biennial series of Summer Schools that are organized within the initiatives of the Lake Como School of Advanced Studies and are fully dedicated to fore-front characterization methods, based on scattering techniques (from X-rays to visible light), developed for the multiple (atomic and nanometer) scale investigation of engineered nanomaterials.